Package: libphobos-4.1-dev Version: 0.25-4.1.2-27 Severity: normal
Hi, While trying to narrow down another bug (#581698) I noticed that my program segfaults on exit, if there are Thread-objects that haven't been start()ed. While it probably doesn't make much sense to create Threads and not start them, this shouldn't happen. I ran it with gdb and got the following backtrace: Program received signal SIGSEGV, Segmentation fault. 0xb7f6292b in pthread_detach () from /lib/i686/cmov/libpthread.so.0 (gdb) bt #0 0xb7f6292b in pthread_detach () from /lib/i686/cmov/libpthread.so.0 #1 0x0805ad93 in _d_callfinalizer () #2 0x0805c5a6 in _D3gcx3Gcx11fullcollectMFPvZk () #3 0x0805ca54 in _D3gcx3Gcx16fullcollectshellMFZk () #4 0x0805cd8c in _D3gcx2GC18fullCollectNoStackMFZv () #5 0x0805a203 in gc_term () #6 0x0806166a in _d_run_main () #7 0x0805e33a in main () I think (but haven't tried to fix that yet) that the error is in Thread's destructor (std/thread.d line 589/590): if (state != TS.FINISHED) pthread_detach(id); The status of an unstarted Thread is TS.INITIAL - I don't know if it is necessary to pthread_detach() a thread that hasn't run, but if it isn't I'd suggest to change this to if(state != TS.FINISHED && state != TS.INITIAL) pthread_detach(id); This Bug also applies gdc-4.3 and Digitalmars dmd. I've attached a simple example to demonstrate the bug. Cheers, - Daniel --- System information. --- Architecture: i386 Kernel: Linux 2.6.32-3-686 Debian Release: squeeze/sid 500 testing security.debian.org 500 testing ftp.de.debian.org --- Package information. --- Depends (Version) | Installed ================================-+-================== gdc-4.1 (= 0.25-4.1.2-27) | 0.25-4.1.2-27 zlib1g-dev (>= 1:1.2.3.3) | 1:1.2.3.4.dfsg-3 Package's Recommends field is empty. Package's Suggests field is empty.
import std.stdio; import std.thread; const bool doSegfault=true; void main(){ int fun(){ writefln("bla"); return 0; } int delegate() dg = &fun; Thread t = new Thread(dg); // if t.start() is missing, the program segfaults on exit (all compilers), // probably because of pthread_detach in Threads destructor // - is pthread_detach necessary when state == TS.INITIAL? static if(!doSegfault){ t.start(); t.wait(); } }